Bis maleimide

In the narrow sense, bis-maleimide resin means the thermosetting resin eom-posed of the bis-maleimide of methylene dianiline (BMI, bis(4-maleimidophenyl)-methane) and methylene dianiline (MDA, bis(4-aminophenyl)methane) (Fig. 1). Beeause of the addition meehanism, the resin is eured without elimination, whieh is a eharacteristic of this resin. Bis-maleimide resin is used as a thermally stable matrix up to 204°C (400 F) whieh typical epoxy resins may not normally be used. However, in spite of having an imide structure, bis-maleimides are classified as being moderately thermally stable resins. The aliphatic structure of the resin is not stable for long periods above 232°C (450°F.) If a highly aromatic thermally stable thermosetting resin is necessary, acetylene end-capped aromatic imide-based oligomers should be used. 

The original compound, maleimide (2,5-dioxo-A -pyrroline), is synthesized by the cyclo-condensation of ammonia and maleic acid. Similarly, primary amine is added to maleic anhydride, followed by cyclocondensation, to form N-substituted maleimide (Fig. 2). This reaction is applied to the preparation of bis-maleimides (BMl) [1]. At first, BMI was used as a crosslinking agent for natural rubber (NR). An o-dichlorobenzene solution of NR was crosslinked by BMI at I08-150°C in the presence of peroxides. The radicals generated from peroxides react with the double bonds of both BMI and NR [ 1 ]. 

Bis-maleimide resins composed of BMI and diamines have been reported in the early 1960s in the patent literature. Since that time, a number of patents have appeared describing improvements in their properties and uses [3]. Although many bis-maleimide resins are commercially developed, relatively few reports of their use as adhesives are to be found in scientific journals [4-10]. Improvements of maleimide resins are mirrored in the improvements of thermosetting polyimides. For example, the method of in situ polymerization of monomer reactants (PMR method) was developed [6]. 

BMI also reacts with dienes to form Diels-Alder adducts [12]. When BMI reacts with a a,(n-biscyclopentadienyl compound or other bis-diene resin, the bis-maleimide chain is extended by the Diels-Alder reaction. Bis-maleimide, chain extended with bis-diene, is not used in adhesives. However, as the Diels-Alder reaction is reversible, there may be a possibility of recyclability of the cured resin by depolymerization of the backbone (Fig. 6). 

One can vary the chemical composition of the bis-maleimide system by replacing tbe MDA with other diamines. The nature of the resin is not that different from that using MDA because the resins are so highly crosslinked. Based upon availability, ease of use and cost, BMI and MDA are most often used. However, one commercial maleimide resin, Techocbemie s Compimide H795 has an original structure. As shown in Fig. 8, it is composed of BMI and / -aminobenzoyl hydrazide [10]. 

To improve upon their inherent brittleness, bis-maleimide resins are often mixed with other eompounds and materials. Glass fabrie and earbon fiber fabrie are immersed in uncured maleimide resin and plied are layed up, followed by... 

The arm-first synthesis of star microgels by initiating polymerization or copolymerization of a divinyl monomer such as diviny lbenzene or a bis-maleimide with a polystyryl alkoxyamine was pioneered by Solomon and coworkers.692 693 The general approach had previously been used in anionic polymerization. The method has now been exploited in conjunction with NMP,692 6 ATRP69 700 and RAFT.449 701 702 The product contains dormant functionality in the core. This can be used as a core for subsequent polymerization of a monoene monomer to yield a mikto-arm star (NMP ATRP704). 

An example of the second type of modification is the application of the Diels-Alder cycloaddition reaction to polders and copol ers containing pendant or backbone furan moieties. The use of bis-dienophiles such as propiolic acid and its esters or bis-maleimides provides a means of crosslinking based on multiple bridging by the double interchain lycloadditions. The thermal reversibility of these reactions allows the return to the original linear structure (thermoplastic material) by simply heating the gel. 

Polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF) cross-link upon irradiation, particularly with the use of prorads, such as TAG, TIAG, diallyl itaconate, ethylene bis-maleimide, and others. ... 

A variety of routes for incorporation of the succinimide group into a polymer backbone are provided by the use of bis(maleimide) monomers (8 Scheme 5). Examples include Michael addition of diamines or dithiols (or H2S) to produce poly(imides) (9) (B-80MI11101), and photopolymerization (via the triplet state) to prepare cyclopolymers (10) (73PAC213) having molecular weights of about 30 000. 

NanoDMA has been successfully used in characterizing viscoelastic properties for a range of polymeric materials, including polyethylene [62], bis-maleimide and thermoplastics [63], There have also been recent reports of nanoDMA being used to examine biological materials such as hairs and whiskers [64], However, the data presented in this section are amongst the first ever obtained for a biofilm. 

Bishomooxacalix[4]arenes 1378 Bishydroxymethylated phenols, thermal dehydration of 1379, 1380 Bis(maleimides) 1495, 1497 Bismuth compounds, as oxidants 1330-1332 Bis(l-nitroso-2-naphtholato)metal(II)... 

Maleimides—see Bis(maleimides), At-(Hydroxyphenyl)maleimide, Poly[At-(subshtuted phenyl)maleimides] Mandehc adds—see Hydroxymandehc acids Manganese compounds, as oxidants 1278, 1279, 1282-1288 Mannich bases 353... 

Bis(maleimides) (BMI) are an important class of polyimides that are characterized by excellent thermal, electrical and mechanical properties Bis(maleimides) are low molecular weight oligomers, generally containing terminal reactive groups. A general structure of a bis(maleimide) is shown in Scheme 28. 

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